The balloons theory of human nature

There was once a girl who travelled to a foreign land, and the people in that land loved helium balloons. Bunches of floating balloons were frequently seen tied up to gates and railings, or floating freely indoors.

The girl had known nothing of helium gas until this point. Observing all the helium-filled balloons, she came to conclusion that the natural shape of helium gas looks like this:

Of course helium does not really have a natural shape; the nature of helium is to fill whatever container it is in.

Humans are infinitely varied, and infinitely adaptable. There is no one natural shape for a human personality, just as there is no natural shape for helium gas. Nevertheless, when visiting a particular spacetime we tend to see the same shapes repeated over and over again. We might take note of these shapes, and think that we are learning something about human nature. However what we are studying is not human nature but the container it has been poured into; the environment, society and culture.